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1
Bethune, M., and Q. J. Wang. "A lysimeter study of the water balance of border-check irrigated perennial pasture." Australian Journal of Experimental Agriculture 44, no. 2 (2004): 151. http://dx.doi.org/10.1071/ea03049.
Повний текст джерелаАнотація:
The dairy industry is a major user of water in northern Victoria and southern New South Wales. Water is typically applied to pasture using the border-check irrigation system. The border-check system is largely gravity driven and thus energy efficient. However, deep drainage can potentially be high because the system allows only limited control over the depth of water applied in each irrigation event. For this reason, heavy soils are regarded as the most suitable for border-check irrigation. This study quantified net deep drainage (deep drainage less capillary rise) under border-check irrigated pasture on a Goulburn clay loam soil. Additionally, the study investigated the extent to which irrigation frequency and watertable conditions influence water use, dry matter production and deep drainage. The water balance and dry matter production were monitored over 2.5 years in a lysimeter facility in northern Victoria. The Goulburn clay loam is representative of the heavier textured soils used for border-check irrigation of pasture in northern Victoria. The average measured net deep drainage was 4 mm/year. This indicates that relatively small levels of net deep drainage can be achieved under well-managed border-check irrigation on a Goulburn clay loam soil. Net deep drainage losses were greatest following winter, when rainfall exceeded pasture water use for an extended period. Increasing the interval between irrigation events resulted in reduced plant water use, infiltration of irrigation water, rainfall runoff and pasture production. However, increasing the interval did not impact on net deep drainage or water use efficiency. Depth of watertable had a relatively minor impact on the water balance.
2
MacEwan, RJ, WK Gardner, A. Ellington, DG Hopkins, and AC Bakker. "Tile and mole drainage for control of waterlogging in duplex soils of south-eastern Australia." Australian Journal of Experimental Agriculture 32, no. 7 (1992): 865. http://dx.doi.org/10.1071/ea9920865.
Повний текст джерелаАнотація:
Waterlogging is a major problem of dryland agriculture in many areas of Australia. Yellow duplex soils, especially those with bleached A2 horizons, are the soils most commonly associated with waterlogging. The problem is principally the development of perched watertables in the A horizons after rain, due to the restricted downward drainage of water caused by the low hydraulic conductivity of heavy clay subsoils. Pipe and mole drainage techniques are briefly reviewed, and experience with subsoil drainage in yellow duplex soils in Victoria is outlined.
3
Ndeda, Violet M., Mariana Mateos, and Luis A. Hurtado. "Evolution of African barbs from the Lake Victoria drainage system, Kenya." PeerJ 6 (October 26, 2018): e5762. http://dx.doi.org/10.7717/peerj.5762.
Повний текст джерелаАнотація:
The Lake Victoria drainage basin (LVD) in Kenya is home to ten nominal species of small barbs (Enteromius) and one of large barbs (Labeobarbus altianalis). A recent molecular study genetically characterized small barbs in this region and found evidence of introgression between certain species, complicating the taxonomy and species identification of these fishes. This study aimed to extend our understanding on the evolution of these fishes by: (1) determining whether putatively pure individuals of Enteromius cercops are found in the Kenyan LVD, as the previous study only found hybrid individuals of this species in this region; (2) testing the sister relationship between Enteromius profundus, endemic to Lake Victoria, and Enteromius radiatus, also found in Lake Victoria, which had been previously synonymized; (3) examining the phylogenetic relationships of small barbs of the Kenyan LVD with those reported from other ichthyological provinces of Africa; and (4) examining the phylogenetic relationships of Labeobarbus altianalis with other Labeobarbus species. To this end, we obtained mitochondrial Cytochrome b and nuclear Growth Hormone (GH) intron 2 gene sequences of nine Enteromius species from the LVD in Kenya, as well as cytochrome b sequences for L. altianalis. We conducted Maximum likelihood and Bayesian phylogenetic analyses to establish their evolutionary relationships in relation to many other barbs specimens from Africa. Phylogenetic analyses did not reveal instances of hybridization/introgression among the individuals sequenced by us. A sister relationship between E. profundus and E. radiatus was not found. This latter species shows instead a sister relationship with a lineage comprised of two species from West Africa. Other sister relationships between taxa from the East coast and other ecoregions from Africa are observed, suggesting that past drainage connections and vicariant events contributed to the diversification of Enteromius. Finally, only a single haplotype was recovered among the L. altianalis individuals examined, which is most similar to a specimen from Lake Edward in Uganda.
4
Gardner, WK, RG Fawcett, GR Steed, JE Pratley, DM Whitfield, Hvan Rees, and Rees H. Van. "Crop production on duplex soils in south-eastern Australia." Australian Journal of Experimental Agriculture 32, no. 7 (1992): 915. http://dx.doi.org/10.1071/ea9920915.
Повний текст джерелаАнотація:
The environment, duplex soil types and trends in crop production in South Australia, southern New South Wales, north-eastern and north-central Victoria, the southern Wimmera and the Victorian Western District are reviewed. In the latter 2 regions, pastoral industries dominate and crop production is curtailed by regular and severe soil waterlogging, except for limited areas of lower rainfall. Subsurface drainage can eliminate waterlogging, but is feasible only for the Western District where subsoils are sufficiently stable. The other regions all have a long history of soil degradation due to cropping practices, but these effects can now be minimised with the use of direct drilling and stubble retention cropping methods. A vigorous pasture ley phase is still considered necessary to maintain nitrogen levels and to restore soil structure to adequate levels for sustainable farming. Future productivity improvements will require increased root growth in the subsoils. Deep ripping, 'slotting' of gypsum, and crop species capable of opening up subsoils are techniques which may hold promise in this regard. The inclusion of lucerne, a perennial species, in annual pastures and intercropping at intervals is a technique being pioneered in north-central and western Victoria and may provide the best opportunity to crop duplex soils successfully without associated land degradation.
5
McFarlane, DJ, and JW Cox. "Management of excess water in duplex soils." Australian Journal of Experimental Agriculture 32, no. 7 (1992): 857. http://dx.doi.org/10.1071/ea9920857.
Повний текст джерелаАнотація:
Excess water in duplex soils can be removed by drains. In soils in which drainage is impractical, some success has been obtained by deep ripping and by gypsum amendment. These practices can increase profile storage or drainage. Interceptor drains are suitable for duplex soils with slopes of more than about 1.5%. On more gentle slopes, relief drains are used to remove excess water. Subsurface tube and mole drains have been used successfully to drain cereal crops in Victoria, but in Western Australia open drains are preferred because they can carry storm runoff as well as seepage waters. The greatest cost of open drains is the land removed from production. Over 35% of the rain falling during the growing season has been removed by drains in Victoria and Western Australia in wet years. Drainage was almost entirely downslope of monitored interceptor drains in Western Australia, which is not predicted from the theory. Simulation of water levels between drains and of drain flows using the DRAINMOD model indicated significant, preferred pathways for water flow to drains. The pathways explain the predominantly downslope effect of interceptor drains and the wide drain spacings which can be used. Deep ripping and the incorporation of gypsum can reduce waterlogging in some soils, but has had no effect in several others. The effect of deep ripping on recharge is unclear. Drains may decrease groundwater recharge, water and wind erosion, and soil structure decline. Their effect on phosphate export from catchments is unclear.
6
Phillips, D. I. "A new litter trap for urban drainage systems." Water Science and Technology 39, no. 2 (January 1, 1999): 85–92. http://dx.doi.org/10.2166/wst.1999.0091.
Повний текст джерелаАнотація:
Litter is generated in shopping areas and is washed or blown into stormwater drainage systems. These convey the litter to open water bodies leading to the accumulation of non-biodegradable litter on the banks and beaches of urban waterways and bay foreshores. The increasing public awareness of the problem prompted the State Government of Victoria to provide funding to develop an innovative patented litter trap known as the In-line Litter Separator (ILLS). The ILLS is retrofitted to the drainage system downstream of shopping areas and removes litter and other pollutants from the passing stormwater. In a two-year development program, ten prototypes were installed and tested in the Melbourne and metropolitan area. The results were so successful that the ILLS is now manufactured in Australia and overseas under license from Swinburne University. This paper presents the performance criteria, the design concepts, the outcomes of laboratory and hydrologic modelling and the analyses of prototype test results that led to the commercial production of the ILLS.
7
Gardner, WK, MF Drendel, and GK McDonald. "Effects of subsurface drainage, cultivation, and stubble retention on soil porosity and crop growth in a high rainfall area." Australian Journal of Experimental Agriculture 34, no. 3 (1994): 411. http://dx.doi.org/10.1071/ea9940411.
Повний текст джерелаАнотація:
Wheat, triticale, and rapeseed growth and yield were studied under various tillage (conventional, deep ripping, direct drilling) and stubble-handling (burnt, retained) regimes with and without drainage at Hamilton in south-western Victoria from 1985 to 1987. Grain yield was increased from about 2 to >4 t/ha by drainage in both years; however, effects of other treatments, although significant, were much less. Soil structure (as measured by fractional air-filled porosity at -5 J/kg) deteriorated during winter and recovered during spring and summer. A laboratory experiment showed that this variation in soil structure resulted from saturation per se and redrying. In the field, the decline in porosity was most pronounced with cultivation and the absence of drainage, but overall, the effects of stubble retention and tillage treatments were small. There was a significant positive relationship between yield and porosity on undrained areas, but not where drains were present. Drainage reduced soil structural decline during winter, while stubble retention reduced the decline in porosity in the cultivated-undrained treatment in 1987.
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Holland, J. E., R. E. White, and R. Edis. "Improved drainage and greater air-filled porosity of raised beds in south-western Victoria." Soil Research 46, no. 4 (2008): 397. http://dx.doi.org/10.1071/sr08003.
Повний текст джерелаАнотація:
Crop production in south-western Victoria has historically been constrained by waterlogging. As a result raised beds have recently become a popular tillage method on soils prone to waterlogging. Soil water properties, air-filled porosity, plant dry matter, and grain yield were compared for raised beds and conventional cultivation treatments during 2003 and 2004. Although rainfall was less than the long-term average, over the whole period the raised beds had consistently lower water content and drained faster than the conventional cultivation. Air-filled porosity was greater and above the critical value of 10% for longer in the raised beds (e.g. in 2004 air-filled porosity was >10% for 69 days longer in the raised beds). Benefits on the raised bed soil (such as greater soil aeration) were probably due to the increased depth to the B horizon and the soil surface topography created by regular furrows. No waterlogging was observed in 2003 and the crop on the conventional cultivation produced significantly more dry matter. Although visible waterlogging of the crop on the conventional cultivation was observed in 2004, the crop on the raised beds was not affected. Despite the different response in growth for each treatment, there was no significant difference in grain yield in either year. Nevertheless, it is predicted that raised beds should provide a well-drained and aerated soil that maintains crop productivity under average or greater rainfall in south-western Victoria.
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Javed, Muhammad Umar, Sidra Aleem, Sheraz Jamil Asif, and Javed Iqbal. "BREAST ABSCESS;." Professional Medical Journal 24, no. 01 (January 18, 2017): 89–94. http://dx.doi.org/10.29309/tpmj/2017.24.01.484.
Повний текст джерелаАнотація:
Objectives: To compare the recurrence rate between incision drainage andmultiple needle aspiration for breast abscess treatment. Study Design: Randomized ControlledTrial. Setting: Department of General Surgery, Bahawal Victoria Hospital, Bahawalpur. StudyDuration: 29th September 2015 to 29th June 2016. Materials & Methods: A total of 60 femalepatients with breast abscess of <2 cm in size and of duration <2 weeks between 20 to 40 yearsof age were included. Patients with multiple breast abscesses, recurrent breast abscesses andcomplicated abscesses were excluded. The patients were randomized into Group A (incisionand drainage) & Group B (needle aspiration), by using lottery method. Follow up was done forup to 7 days and recurrence was noted. Results: The mean age of patients in group A was30.83 ± 5.67 years and in group B was 31.53 ± 5.73 years. Mean duration of disease was 7.58± 2.83 days. Mean size of abscess was 0.86 ± 0.43 cm. Recurrence was found in 07 (23.33%)patients in group A (incision drainage) while in 21 (70.0%) patients in group B (multiple needleaspiration) with p-value of 0.000 which is statistically significant. Conclusion: The recurrencerate is less after incision & drainage as compared to multiple needle aspirations for treatingbreast abscess.
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Rwetabula, J., F. De Smedt, and M. Rebhun. "Prediction of runoff and discharge in the Simiyu River (tributary of Lake Victoria, Tanzania) using the WetSpa model." Hydrology and Earth System Sciences Discussions 4, no. 2 (April 23, 2007): 881–908. http://dx.doi.org/10.5194/hessd-4-881-2007.
Повний текст джерелаАнотація:
Abstract. A spatially distributed hydrologic model (WetSpa) is used to estimate daily river water discharge in the Simiyu river a tributary of Lake Victoria, Tanzania. The model combines topography, landuse and soil maps, and observed daily meteorological time series to predict discharge hydrographs and the spatial distribution of hydrological parameters in the catchment. The elevations in the catchment range from 2000 to 1100 m at the outlet, with average slope of 1.4%. The dominant landuse types are, wasteland, grassland, bushland, cultivated land, and a very small area is covered by surface water. The dominant soil types are sandy loam, followed by sandy clay loam, clay loam, clay, loam and sandy clay. There are two distinctive seasons in the Simiyu catchment. Short rains mainly in November, December and January, and long rains in March to May, resulting in a total average annual precipitation of 700 to 1000 mm. The annual potential evapotranspiration is about 1300 mm, and the river discharge at the catchment outlet ranges from 0 to about 200 m3/s. Global parameters of the model are calibrated using three years of daily observed discharge values measured at the mouth of the river at Lake Victoria. The estimated average travel time of the runoff to the outlet of the catchment is about 2.4 d and maximum 8 d for the most remote areas. The model results also show that the surface runoff and interflow provide respectively 38.6% and 61.4% of the total runoff, while the contribution of groundwater drainage is nil. The absence of groundwater drainage is probably due to the high evaporation demand of the atmosphere, which accounts for about 90% of the total precipitation being lost by evapotranspiration. The annual water balance estimated with the model reveals that the total outflow to Lake Victoria is about 500×106 m3 per year, which occurs mainly in the wet seasons, i.e. from March to May and from November to January. The volume of runoff produced by agricultural land amounts to about 9% of the total runoff annually.
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Marchant, R., D. Ryan, and L. Metzeling. "Regional and local species diversity patterns for lotic invertebrates across multiple drainage basins in Victoria." Marine and Freshwater Research 57, no. 7 (2006): 675. http://dx.doi.org/10.1071/mf06035.
Повний текст джерелаАнотація:
Regional (RSR) and local species richness (LSR) was recorded for stream invertebrate communities at reference sites in 25 drainage basins in Victoria. Regional species richness was defined as the total number of species recorded at all reference sites within a basin, and LSR as the total numbers of species recorded at a single reference site. Records were obtained from bank and channel habitats and analysed separately. Regressions between LSR and RSR indicated a proportional or linear relationship in both habitats. This applied to the whole data set and to subgroups representing Ephemeroptera, Plecoptera and Trichoptera (EPT as a group), Hemiptera, Diptera, and Coleoptera. All data sets thus represented communities in which no upper limit to LSR was observed. Multiple regressions between LSR and RSR, number of samples per site (N) and seven physical variables showed that RSR and N were nearly always significantly related to LSR. Few of the physical variables were significant except conductivity (for EPT and Coleoptera). Multidimensional scaling ordinations revealed an east-west gradient in compositional similarity of invertebrates, upon which variations in RSR had a major influence. Investigation of factors that regulate RSR will thus be necessary for a broad scale view of what regulates LSR.
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Dawson, P., and G. Weste. "Changes in the Distribution of Phytophthora cinnamomi in the Brisbane Ranges National Park Between 1970 and 1980-81." Australian Journal of Botany 33, no. 3 (1985): 309. http://dx.doi.org/10.1071/bt9850309.
Повний текст джерелаАнотація:
The distribution of Phytophthora cinnamomi in the Brisbane Ranges National Park of Victoria was mapped and related to vegetation susceptibility, disease severity and past distribution. P. cinnamomi extended its distribution from 1% of the park in 1970 to 31% in 1980-81. The dispersal of the pathogen has occurred through roadworks and subsequent drainage of water-borne zoospores. In 1980-81, 50% of 1191 grids (250 x 250 m) occurred in susceptible vegetation (sclerophyllous forest/woodland). Of these, 45% (266 grids) were moderately diseased and 16% (95) severely diseased. Stands of dead trees occurred in 29 severely diseased grids which were in shallow gullies with impeded drainage. The 39% (231) of susceptible vegetation which remained unaffected occurred mainly on ridges and hilltops. P. cinnamomi was isolated from 3% of apparently resistant vegetation (graminoid forest/woodland). Restriction of access is recommended to the remaining areas of susceptible unaffected vegetation.
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Gibson, John A. E., Damian B. Gore, and Enn Kaup. "Algae River: an extensive drainage system in the Bunger Hills, East Antarctica." Polar Record 38, no. 205 (April 2002): 141–52. http://dx.doi.org/10.1017/s0032247400017526.
Повний текст джерелаАнотація:
AbstractAn extensive terrestrial drainage system, centred on Algae Lake in southern Bunger Hills, is described. The 25-km-long Algae River is the third longest known in Antarctica after Onyx River (Wright Valley, Victoria Land) and Druzhby River (Vestfold Hills, Queen Elizabeth Land). Algae River receives meltwater from the Antarctic ice sheet, Apfel Glacier, and ephemeral and permanent snow banks in the ice-free area of the Bunger Hills. Water flows through a series of epiglacial lakes before reaching the extensive Algae Lake, which in turn has an outlet to Transkriptsii Gulf, a largely fresh-water, tidal epishelf lake connected to the ocean under the Edisto Ice Tongue and Shackleton Ice Shelf. Total flow from Algae Lake was estimated to be greater than 1 x 107 m3 a-1 from data collected in the 1986/87 summer. Some portions of the drainage system that were flowing during the 1946/47,1985/86, 1986/87, 1994/95, 1995/96, and 1998/99 summers were not flowing during the 1999/2000 summer, indicating the variable nature of discharge in the river and emphasising that parts of the drainage network may become disconnected readily.
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Babu, G. Rajashekara, Sahanashree Venkatesh, Ramakrishnan K., and Pravesh Jain. "Clinical study and management of pseudocyst of pancreas." International Surgery Journal 4, no. 4 (March 25, 2017): 1426. http://dx.doi.org/10.18203/2349-2902.isj20171155.
Повний текст джерелаАнотація:
Background: Pancreatic pseudocysts can occur as a complication of acute or chronic pancreatitis. Understanding of pseudocysts has changed with times due to advancement in radiology and introduction of new treatment modalities. This study was done to access clinical features etiology and various managements for pseudocyst in a tertiary care hospital.Methods: It is a prospective study of 40 adult patients admitted in Victoria and Bowring and Lady Curzon Hospital, attached to Bangalore Medical College and Research Institute, Karnataka, India from January 2015 to December 2016.Results: Pseudocysts are more common in males. The commonest etiology associated was alcohol. Ultrasound was the basic radiological investigation done in all patients followed by CECT abdomen. Complications associated with pseudocyst were Gastric outlet obstruction and ascites. Internal drainage was done in most of the patients. Post drainage complications included infection which was managed by antibiotics and endoscopic drainage in case of recollection. Pain was most important post-operative complication. Endoscopic drainage is being preferred as it is less invasive, has a high long term success rate, has shorter duration of hospital stay and more patient comfort.Conclusions: Pseudocyst of pancreas is most commonly seen in males probably because of alcoholism. Clinical presentation can be varied, with pain abdomen being the most common complaint followed by, nausea vomiting. Initial management consists of supportive care and if the symptoms persist and complications develop surgical drainage was the most common management modality. Newer modalities of treatments like endoscopic intervention have an added advantage of lesser pain, shorter duration of hospital stay and recurrence.
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Zeidler, Wolfgang, and M. Adams. "Revision of the Australian crustacean genus of freshwater crayfish Gramastacus Riek (Decapoda : Parastacidae)." Invertebrate Systematics 3, no. 7 (1989): 913. http://dx.doi.org/10.1071/it9890913.
Повний текст джерелаАнотація:
The Australian freshwater crayfish genus Gramastacus, previously consisting of two species known only from type localities, is revised utilising newly collected material ranging from The Grampians, Victoria, to the south-east, of South Australia. Morphological and biochemical studies demonstrate that Granzastacus is monotypic with G. insolitus Riek, 1972 the only species. Morphological comparisons between Granmstacus and Geocharax are also made, and although Gramastacus is similar to Geocharax, sufficient differences were found to uphold the generic status of Granlastacus. G. insolitus is a swamp-living species whose survival is threatened by further drainage of remaining known localities.
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HANELT, B., S. V. BRANT, M. L. STEINAUER, G. M. MAINA, J. M. KINUTHIA, L. E. AGOLA, I. N. MWANGI, et al. "Schistosoma kisumuensisn. sp. (Digenea: Schistosomatidae) from murid rodents in the Lake Victoria Basin, Kenya and its phylogenetic position within theS. haematobiumspecies group." Parasitology 136, no. 9 (July 2, 2009): 987–1001. http://dx.doi.org/10.1017/s003118200900643x.
Повний текст джерелаАнотація:
SUMMARYSchistosoma kisumuensisn. sp. is described based on 6 adult males and 2 adult females collected from the circulatory system of 3 murid rodent species,Pelomys isseli, Mastomys natalensis, andDasymys incomtus. Specimens were collected from a single location, Nyabera Swamp, in Kisumu, Kenya in the Lake Victoria Basin. This new species is morphologically similar to members of theS. haematobiumgroup, currently represented by 8 species parasitizing artiodactyls and primates, including humans.Schistosoma kisumuensisdiffers from these species by producing relatively smallSchistosoma intercalatum-like eggs (135·2×52·9 μm) with a relatively small length to width ratio (2·55). Comparison of approximately 3000-base-pair sequences of nuclear rDNA (partial 28S) and mtDNA (partialcox1,nad6, 12S) strongly supports the status ofS. kisumuensisas a new species and as a sister species ofS. intercalatum. Thecox1 genetic distance between these two species (6·3%) is comparable to other pairwise comparisons within theS. haematobiumgroup. Separation of the Congo River and Lake Victoria drainage basins is discussed as a possible factor favoring the origin of this species.
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Cantrill, DJ, and JG Douglas. "Mycorrhizal Conifer Roots From the Lower Cretaceous of the Otway Basin, Victoria." Australian Journal of Botany 36, no. 3 (1988): 257. http://dx.doi.org/10.1071/bt9880257.
Повний текст джерелаАнотація:
Fossil roots with nodular and abbreviated lateral roots are described from the Devils Kitchen locality within the Lower Cretaceous Otway Group. The general morphology of these roots indicates a mycorrhizal association, the oldest such record from Australia. Based on the root morphology and associated megaflora it is considered that the roots are coniferous (Taxodiaceae or Podocarpaceae); an association of the roots with foliage of Geinitzia tetragona sp. nov., which is possibly taxodiaceous, is indicated. The major role of nodular mycorrhizal roots in extant plants is phosphate uptake which enhances minor nitrogen uptake. It is suggested that the fossil roots may have had a similar role. The Devils Kitchen locality is interpreted as a levee or near channel deposit with better drainage andlor a nutrient-poor soil relative to other soils in the sequence. The atypical plant associations of Cladophlebis australis, C. sp. b, and Geinitzia tetragona sp. nov. are a reflection of the above.
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Burns, Phoebe A., Karen M. C. Rowe, Benjamin P. Holmes, and Kevin C. Rowe. "Historical resurveys reveal persistence of smoky mouse (Pseudomys fumeus) populations over the long-term and through the short-term impacts of fire." Wildlife Research 42, no. 8 (2015): 668. http://dx.doi.org/10.1071/wr15096.
Повний текст джерелаАнотація:
Context Range contractions are often the first indicator that a species is in decline. However, natural population fluctuations, characteristic of many Australian rodents, make differentiating between natural lows and unsustainable declines challenging. The endangered smoky mouse (Pseudomys fumeus) is a prime example. Surveys have failed to detect the species across much of its range over the past decade, but P. fumeus is known to experience fluctuations in abundance and periods of low detectability. Aims We compared past and current distributions of P. fumeus in the Victoria Range, Grampians–Gariwerd National Park (Victoria, Australia), to assess long-term population persistence over 40 years and short-term population persistence following a high-severity fire. Methods To evaluate the efficacy of surveys in detecting P. fumeus, we conducted analyses to explicitly model detectability using historical (1974, 2002) and modern (2013) survey data. We also tested the short-term impacts of fire on the presence of P. fumeus by surveying burned and unburned sites 3 months prior to, and 7 to 21 months following, a severe wildfire. Key results Our surveys detected P. fumeus at five new sites, confirmed presence at one historical site, and absence from two historical sites. The species persisted in situ through fire, and for at least 21 months following. We detected resident populations in burned and unburned wet drainage systems. Conclusions Despite periods of low density in which the species was undetected, P. fumeus persisted in an 8 km radius area of the eastern escarpment of Victoria Range of the Grampians–Gariwerd National Park for at least four decades through droughts, the presence of invasive predators, and the short-term impacts of wildfire. Implications Although P. fumeus persisted through a severe fire, factors influencing survival must be assessed before generalisations are made about the impacts of wildfire on the species. Management of P. fumeus should recognise that the species survives and breeds in wet drainage systems. Regular resurveys incorporating statistical estimates of detectability are necessary to identify and track distributional changes of threatened species, like P. fumeus, particularly in the context of natural, sustainable fluctuations.
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Ashmore, David W., and Robert G. Bingham. "Antarctic subglacial hydrology: current knowledge and future challenges." Antarctic Science 26, no. 6 (November 13, 2014): 758–73. http://dx.doi.org/10.1017/s0954102014000546.
Повний текст джерелаАнотація:
AbstractFlood-carved landforms across the deglaciated terrain of Victoria Land, East Antarctica, provide convincing geomorphological evidence for the existence of subglacial drainage networks beneath the Antarctic ice sheet, and motivate research into the inaccessible environment beneath the contemporary ice sheet. Through this research, our understanding of Antarctic subglacial hydrology is steadily building, and this paper presents an overview of the current state of knowledge. The conceptualization of subglacial hydrological behaviour was developed at temperate and Arctic glaciers, and is thus less mature in the Antarctic. Geophysical and remote sensing observations have demonstrated that many subglacial lakes form part of a highly dynamic network of subglacial drainage beneath the Antarctic ice sheet. Recent research into subglacial water flows, other than those directly concerned with lakes, has discovered potentially significant impacts on ice stream dynamics, ice sheet mass balance, and supplies of water to the ocean potentially affecting circulation and nutrient productivity. Despite considerable advances in understanding there remain a number of grand challenges that must be overcome in order to improve our knowledge of these subglacial hydrological processes.
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Selkirk, P. M., M. L. Skotnicki, J. Ninham, M. B. Connett, and J. Armstrong. "Genetic variation and dispersal of Bryum argenteum and Hennediella heimii populations in the Garwood Valley, southern Victoria Land, Antarctica." Antarctic Science 10, no. 4 (December 1998): 423–30. http://dx.doi.org/10.1017/s0954102098000510.
Повний текст джерелаАнотація:
A detailed study was made of the extent of genetic variation within populations of two moss species, Bryum argenteum and Hennediella heimii, from the Garwood Valley in Southern Victoria Land, Antarctica. RAPD (Random Amplified Polymorphic DNA) technology was used to analyse over 30 clumps of each species, collected from adjacent sites in five small meltstream drainage channels. Overall, extensive genetic variation was found, with no two samples being identical in either species. For both species, most clumps showed within-clump variation, although generally the shoots from each clump were most closely related to other shoots from that clump, indicating somatic mutation. Of the B. argenteum isolates, most showed distinct clustering corresponding to the five drainage channels, with some clustering within the top, middle or bottom of the channels, and separation of northern and southern sides of the valley. There was some evidence of across-channel dispersal for B. argenteum. For H. heimii, the situation was quite different; there was very little clustering of clumps according to channel from which they were collected. Rather, the isolates appeared to form one continuous population across the five channels, with partial separation of northern and southern sides of the valley. These results are consistent with the predicted means of dispersal of these species in Antarctica: predominantly by water for B. argenteum, and by wind for H. heimii.
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Mireri, Caleb, Peter Atekyereza, Aphonse Kyessi, and Nimrod Mushi. "Environmental risks of urban agriculture in the Lake Victoria drainage basin: A case of Kisumu municipality, Kenya." Habitat International 31, no. 3-4 (September 2007): 375–86. http://dx.doi.org/10.1016/j.habitatint.2007.06.006.
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Ridley, A. M., R. E. White, R. J. Simpson, and L. Callinan. "Water use and drainage under phalaris, cocksfoot, and annual ryegrass pastures." Australian Journal of Agricultural Research 48, no. 7 (1997): 1011. http://dx.doi.org/10.1071/a96157.
Повний текст джерелаАнотація:
The water balance equation was used to calculate plant water use and drainage below a depth of 1·1 m for phalaris, cocksfoot, and annual ryegrass pastures and bare fallow at Rutherglen in north-eastern Victoria. Rainfall from 1990 to 1993 averaged 693 mm/year. Soil water use was greater under perennials over the summer{autumn period and the soil profile was approximately 50 mm drier at the beginning of each drainage season. Following autumn rains, soil water profiles under all treatments converged, usually reaching similar water contents within 4{6 weeks. Over 4 years, soil under phalaris became 33 mm drier, and cocksfoot 24 mm drier (P < 0· 001), than under annual ryegrass or bare fallow. Phalaris had higher actual evapotranspiration (P < 0·05; average, 642 mm/year) than cocksfoot (619 mm/year) and annual ryegrass (606 mm/year), the latter two not differing significantly. Drainage occurred during winter and early spring, ranging from 2 to 12 mm in 1991 (515 mm rainfall) to >100 mm/year in 1990 and 1992 (671 mm and 901 mm rainfall, respectively). The variation between years was greater than the differences between pastures in any one year. Averaged over the 4 years, drainage losses below 1 .1 m decreased in the order bare fallow > annual ryegrass > cocksfoot > phalaris, although differences between the 3 pasture types were not statistically significant. Drainage under phalaris and cocksfoot may have been overestimated relative to annual ryegrass and fallow because of subsurface flow, at the top of the B horizon, between the wetter and drier plots. The drainage under phalaris may also have been overestimated because this pasture extracted water below the depth of soil water measurement. Allowing for these effects, the estimated drainage under phalaris may have been 49-56 mm/year compared with 80-87 mm/year under annual ryegrass, an overall reduction of more than one-third. Although perennial pasture grasses are unlikely to stop all recharge to groundwater in high rainfall areas (>600 mm/year) of south-eastern Australia, they offer a practical way to combine profitable agriculture with reduced land degradation.
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Dunning, Joel, Mahmood Megahed, and Russell W. J. Millner. "The Frequency of Pleural Effusions after Bellovac Drainage following Coronary Bypass Grafting." Cardiovascular Surgery 11, no. 4 (August 2003): 309–12. http://dx.doi.org/10.1177/096721090301100411.
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Background: A common postoperative complication after CABG with internal mammary artery (IMA) harvest is the evolution of a pleural effusion. Our aim was to see if the intra-operative insertion of a Bellovac drain to the pleural cavity, with drainage continuing for 4-days post operation, eliminates the complication of pleural effusion. Methods: Using our computerised audit database, 500 consecutive patients were identified who had undergone CABG including at least one internal mammary graft by a single consultant at Blackpool Victoria Hospital. All these patients received Bellovac drainage for 4 days on the side of the harvested IMA. The chest X-ray reports were retrospectively collected from the hospital computer databases. The 4-day post-operative, and the 6-week post-operative films were found. In the cases where no consultant radiologist report was found J.D. reviewed the film, and any abnormalities were also reviewed by R.W.J.M. Results: Out of 500 radiographs, six patients (1.2%) died, 25 patients had no traceable record of a chest X-ray, 434 patients had an entirely normal chest X-ray and 461 patients had no effusion at 6 weeks. Six patients had a small effusion at 6 weeks, two had a moderate effusion successfully treated conservatively, and no patients had a pleural effusion that required drainage. Conclusion: In patients undergoing coronary arterial bypass grafting with Internal mammary artery harvest, the intra-operative insertion of a Bellovac drain on the side of the harvested IMA reduces the risk of postoperative pleural effusions
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Hoffman, Matthew J., Andrew G. Fountain, and Glen E. Liston. "Near-surface internal melting: a substantial mass loss on Antarctic Dry Valley glaciers." Journal of Glaciology 60, no. 220 (2014): 361–74. http://dx.doi.org/10.3189/2014jog13j095.
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AbstractThe McMurdo Dry Valleys, southern Victoria Land, East Antarctica, are a polar desert, and melt from glacial ice is the primary source of water to streams, lakes and associated ecosystems. Previous work found that to adequately model glacier ablation and subsurface ice temperatures with a surface energy-balance model required including the transmission of solar radiation into the ice. Here we investigate the contribution of subsurface melt to the mass balance of (and runoff from) Dry Valley glaciers by including a drainage process in the model and applying the model to three glacier sites using 13 years of hourly meteorological data. Model results for the smooth glacier surfaces common to many glaciers in the Dry Valleys showed that sublimation was typically the largest component of surface lowering, with rare episodes of surface melting, consistent with anecdotal field observations. Results also showed extensive internal melting 5–15 cm below the ice surface, the drainage of which accounted for ~50% of summer ablation. This is consistent with field observations of subsurface streams and formation of a weathering crust. We identify an annual cycle of weathering crust formation in summer and its removal during the 10 months of winter sublimation.
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Dove, A. D. M., and A. S. Fletcher. "The distribution of the introduced tapeworm Bothriocephalus acheilognathi in Australian freshwater fishes." Journal of Helminthology 74, no. 2 (June 2000): 121–27. http://dx.doi.org/10.1017/s0022149x00000160.
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AbstractNative and exotic fishes were collected from 29 sites across coastal and inland New South Wales, Queensland and Victoria, using a range of techniques, to infer the distribution of Bothriocephalus acheilognathi (Cestoda: Pseudophyllidea) and the host species in which it occurs. The distribution of B. acheilognathi was determined by that of its principal host, carp, Cyprinuscarpio; it did not occur at sites where carp were not present. The parasite was recorded from all native fish species where the sample size exceeded 30 and which were collected sympatrically with carp: Hypseleotris klunzingeri, Hypseleotris sp. 4, Hypseleotris sp. 5, Phylipnodon grandiceps and Retropinna semoni. Bothriocephalus acheilognathi was also recorded from the exotic fishes Gambusia holbrooki and Carassiusauratus. Hypseleotris sp. 4, Hypseleotris sp. 5, P. grandiceps, R. semoni and C. auratus are new host records. The parasite was not recorded from any sites in coastal drainages. The only carp population examined from a coastal drainage (Albert River, south-east Queensland) was also free of infection; those fish had a parasite fauna distinct from that of carp in inland drainages and may represent a separate introduction event. Bothriocephalus acheilognathi has apparently spread along with its carp hosts and is so far restricted to the Murray-Darling Basin. The low host specificity of this parasite is cause for concern given the threatened or endangered nature of some Australian native freshwater fish species. A revised list of definitive hosts of B. acheilognathiis presented.
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Mbabazi, Jolocam, J. Wasswa, J. Kwetegyeka, and G. K. Bakyaita. "Heavy metal contamination in vegetables cultivated on a major urban wetland inlet drainage system of Lake Victoria, Uganda." International Journal of Environmental Studies 67, no. 3 (June 2010): 333–48. http://dx.doi.org/10.1080/00207231003612613.
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Swamikannu, X., D. Radulescu, R. Young, and R. Allison. "A comparative analysis: storm water pollution policy in California, USA and Victoria, Australia." Water Science and Technology 47, no. 7-8 (April 1, 2003): 311–17. http://dx.doi.org/10.2166/wst.2003.0704.
Повний текст джерелаАнотація:
Urban drainage systems historically were developed on principles of hydraulic capacity for the transport of storm water to reduce the risk of flooding. However, with urbanization the percent of impervious surfaces increases dramatically resulting in increased flood volumes, peak discharge rates, velocities and duration, and a significant increase in pollutant loads. Storm water and urban runoff are the leading causes of the impairment of receiving waters and their beneficial uses in Australia and the United States today. Strict environmental and technology controls on wastewater treatment facilities and industry for more than three decades have ensured that these sources are less significant today as the cause of impairment of receiving waters. This paper compares the approach undertaken by the Environmental Protection Authority Victoria for the Melbourne metropolitan area with the approach implemented by the California Environmental Protection Agency for the Los Angeles area to control storm water pollution. Both these communities are largely similar in population size and the extent of urbanization. The authors present an analysis of the different approaches contrasting Australia with the USA, comment on their comparative success, and discuss the relevance of the two experiences for developed and developing nations in the context of environmental policy making to control storm water and urban runoff pollution.
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Ridley, A. M., B. Christy, F. X. Dunin, P. J. Haines, K. F. Wilson, and A. Ellington. "Lucerne in crop rotations on the Riverine Plains. 1. The soil water balance." Australian Journal of Agricultural Research 52, no. 2 (2001): 263. http://dx.doi.org/10.1071/ar99165.
Повний текст джерелаАнотація:
Dryland salinity, caused largely by insufficient water use of annual crops and pastures, is increasing in southern Australia. A field experiment in north-eastern Victoria (average annual rainfall 600 mm) assessed the potential for lucerne grown in rotation with crops to reduce the losses of deep drainage compared with annual crops and pasture. Soil under lucerne could store 228 mm of water to 1.8 m depth. This compared with 84 mm under continuous crop (to 1.8 m depth), except in 1997–98 where crop dried soil by 162 mm. Between 1.8 and 3.25 m depth lucerne was able to create a soil water deficit of 78 mm. The extra water storage capacity was due to both the increased rooting depth and increased drying abiliy of lucerne within the root-zone of the annual species. Large drainage losses occurred under annuals in 1996 and small losses were calculated in 1997 and 1999, with no loss in 1998. Averaged over 1996–1999, drainage under annual crops was 49 mm/year (maximum 143 mm) and under annual pastures 35 mm/year (maximum 108 mm). When the extra soil water storage under lucerne was accounted for, no drainage was measured under this treatment in any year. Following 2 years of lucerne, drainage under subsequent crops could occur in the second crop. However, with 3 or 4 years of lucerne, 3–4 crops were grown before drainage loss was likely. Our calculations suggest that in this environment drainage losses are likely to occur under annual species in 55% of years compared with 6% of years under lucerne. In wet years water use of lucerne was higher than for crops due to lucerne’s ability to use summer rainfall and dry soil over the summer–autumn period. During the autumn–winter period crop water use was generally higher than under lucerne. The major period of increased soil water extraction under lucerne was from late spring to midsummer, with additional drying from deeper layers until autumn. Under both lucerne and crops, soil dried progressively from upper to lower soil layers. Short rotations of crops and lucerne currently offer the most practical promise for farmers in cropping areas in southern Australia to restore the water balance to a level which reduces the risk of secondary salinity.
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Brennand, T. A., and D. R. Sharpe. "Ice-sheet dynamics and subglacial meltwater regime inferred from form and sedimentology of glaciofluvial systems: Victoria Island, District of Franklin, Northwest Territories." Canadian Journal of Earth Sciences 30, no. 5 (May 1, 1993): 928–44. http://dx.doi.org/10.1139/e93-078.
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On Victoria Island, tunnel channels, eskers, and associated fans and extended deposits together constitute channelized glaciofluvial systems. Flutes and drumlinoid ridges, interpreted as residuals left by erosive, catastrophic, subglacial meltwater sheet flows, lie adjacent to these systems. One tunnel channel is described in detail. It exhibits deep scours, a discontinuous thalweg, sculpted margins, and flutes on the downflow side of one wall, features indicative of complex flow and possibly several flow events. The tunnel channel is interpreted as the product of erosion by catastrophic, subglacial meltwater flow in a combined ice – substrate (R/N) channel.Esker sediments and morphology are used to infer details of the depositional environment and meltwater regime. A continuous esker with fans and extended deposits records seasonally controlled discharge events through an R-channel. These features may also suggest a grounding-line environment, thin ice, and localized ice floatation events. Less well connected ridges also record seasonally controlled meltwater rhythms and were produced within a thinning and stagnating ice mass; the depositional environment may have been in a subglacial R-channel or an ice-walled reentrant.Differences in the drainage system associated with each glaciofluvial landform, and temporal disconnection between tunnel channel and esker formation, is also suggested by possible paleoflow reversals between inferred catastrophic and seasonally controlled drainage phases. Changes in ice-sheet profiles between events may have been responsible.
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Silvester, Ewen. "Ionic regulation in an alpine peatland in the Bogong High Plains, Victoria, Australia." Environmental Chemistry 6, no. 5 (2009): 424. http://dx.doi.org/10.1071/en09062.
Повний текст джерелаАнотація:
Environmental context. Australian alpine peatlands are thought to have an important role in maintaining water quality in the associated headwater streams. This study has confirmed that these peatlands can significantly modify stream water through a range of mechanisms, including: nutrient uptake, salt sequestering, and the export of organic carbon. While the significance of this chemical regulation to down stream processes is yet to be fully understood, it is clear that these systems have considerable potential to modify water composition. Abstract. Heathy Spur 1 (HS-1) is an intact alpine peatland in the Bogong High Plains, Victoria, Australia, that serves as a reference system for understanding the impacts of historical land use practices (cattle grazing, water diversion) and wildfire. The major ion chemistry in the groundwater feed and drainage water at HS-1 was studied over seasonal timescales during ‘dry weather’ periods; conditions that allow a simple hydrological model to be used, where the groundwater is assumed to partition between evapotranspiration and stream discharge. With this model the acid neutralising capacity (ANC) of stream discharge can be understood in terms of evapotranspiration and proton uptake associated with nitrate and sulfate removal. Stream discharge ANC is strongly partitioned towards exported dissolved organic carbon, shifting the buffering intensity to lower pH compared to the groundwater. Given the extremely low alkalinity of the regional groundwater, these alpine peatlands likely have a critical role in increasing headwater stream buffering capacity.
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Okeyo, Daniel O. "Artisanal and commercial fishing gear and practices in the Lake Victoria basin drainage systems of Kenya: A photodiagrammatic verification." Lakes & Reservoirs: Research & Management 19, no. 3 (September 2014): 192–205. http://dx.doi.org/10.1111/lre.12067.
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Getenga, Z. M., F. O. Keng’ara, and S. O. Wandiga. "Determination of Organochlorine Pesticide Residues in Soil and Water from River Nyando Drainage System Within Lake Victoria Basin, Kenya." Bulletin of Environmental Contamination and Toxicology 72, no. 2 (February 2004): 335–43. http://dx.doi.org/10.1007/s00128-003-9107-3.
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Verburg, K., W. J. Bond, J. R. Hirth, and A. M. Ridley. "Lucerne in crop rotations on the Riverine Plains. 3. Model evaluation and simulation analyses." Australian Journal of Agricultural Research 58, no. 12 (2007): 1129. http://dx.doi.org/10.1071/ar07133.
Повний текст джерелаАнотація:
The use of a lucerne phase in crop rotations can reduce water lost as drainage past the root zone under dryland agriculture in southern Australia. During the lucerne phase the perenniality of lucerne and its deep rooting ability allow extraction of soil water from below the root zone of annual crops and the creation of a soil water storage buffer against deep water loss. The longevity of the soil water storage buffer depends on rainfall patterns, management of the crops and summer fallows, as well as the magnitude of the buffer created during the lucerne phase. Results from a previously reported field experiment in north-eastern Victoria (average annual rainfall 600 mm) suggested that a 2-year lucerne phase could be insufficient to prevent drainage under subsequent crops for more than 1 year. Computer simulations were used to explore the implications of climatic variability on the creation and refilling of the soil water storage buffer. After first testing that the simulations described the experimental data satisfactorily, they were then used to extend the results and conclusions of the field experiment. These showed that the outcome of the experimental evaluation was affected by the climatic conditions experienced during the experiment and that a lucerne phase duration of 2 years was not appreciably less effective than a 3-year lucerne phase in reducing drainage past 1.8 m (the depth evaluated in the experiment). This conclusion was, however, sensitive to the depth at which drainage was evaluated and also depended on management factors such as the timing of lucerne removal and weed control during the summer fallows. For example, when drainage was evaluated to the maximum depth of lucerne rooting (3.6 m), lucerne was removed in December rather than April, and weeds were permitted, a third year of lucerne allowed a longer cropping phase without refilling of the profile in 47% of years. As a general recommendation a 3-year lucerne phase might, therefore, be an appropriate option for maximising the prevention of drainage. The large variability in the longevity of the soil water storage buffer (from 3 to > 45 months) and its sensitivity to management suggest, however, that it may be more beneficial to link phase changes to local assessment of the status of soil water storage buffer.
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BORGHINI, FRANCESCA, and ROBERTO BARGAGLI. "Changes of major ion concentrations in melting snow and terrestrial waters from northern Victoria Land, Antarctica." Antarctic Science 16, no. 2 (June 2004): 107–15. http://dx.doi.org/10.1017/s095410200400197x.
Повний текст джерелаАнотація:
Concentrations of major ions (Cl−, NO3−, SO42−, Na+, K+, Mg2+, Ca2+) were measured in melting snow and water samples from streams and lakes in ice-free areas throughout northern Victoria Land. Most ions in snow and terrestrial water derive from the marine environment and their concentrations are extremely variable in space and time, especially in water systems without melting snow and ice. The distance from the sea, snow sublimation, changes in water inflow, evaporative concentrations, weathering and drainage processes in the catchment, nesting seabirds and aquatic microbiota are among factors which most influence ion composition variability. Comparisons with data from twelve years ago in the same lakes indicate that the warming trend detected at Terra Nova Bay station during this period did not affect the biogeochemistry of water systems. Waters from a lake which recently experienced a lowering of the water level showed a remarkable increase in SO42− concentrations. We hypothesized that the differential mobility of sulphate salts in the Antarctic soils, the biosynthesis of sulphur compounds in the lake, and the progressive decrease of the water volume are factors involved in the increase of SO42− concentrations.
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SCHMIDT, RAY C., HENRY L. JR BART, and WANJA DOROTHY NYINGI. "Integrative taxonomy of the red-finned barb, Enteromius apleurogramma (Cyprininae: Smiliogastrini) from Kenya, supports recognition of E. amboseli as a valid species." Zootaxa 4482, no. 3 (September 19, 2018): 566. http://dx.doi.org/10.11646/zootaxa.4482.3.8.
Повний текст джерелаАнотація:
Research on freshwater ecosystems in East Africa is providing a better understanding of the biodiversity in the region. Recent studies of the Kenyan barbs (Cyprininae: Smiliogastrini) revealed diversity within several nominal species from the region. In this study, we examine the molecular and morphological variation in the red-finned barb (Enteromius apleurogramma). The results of this study support the recognition of E. amboseli as a valid species that is endemic to the middle Athi River drainage in southern Kenya. Enteromius amboseli is geographically isolated and distinguished from E. apleurogramma in having longer posterior barbels, a shorter dorsal fin, and generally fewer scales in the longitudinal series. Genetic divergence between E. apleurogramma populations in Lake Victoria and Lake Kanyaboli, provide novel estimates for rates of molecular evolution in the group. Additionally, the biogeography of these barbs and the conservation status of E. amboseli are discussed.
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JOHNSON, DANIEL P. "The subgenus Ortmannicus (Decapoda: Cambaridae) in Texas, with descriptions of new species." Zootaxa 4468, no. 1 (September 3, 2018): 1. http://dx.doi.org/10.11646/zootaxa.4468.1.1.
Повний текст джерелаАнотація:
Three crayfishes of the genus Procambarus, subgenus Ortmannicus, are described from Texas, including (1) Procambarus (Ortmannicus) parvus n. sp. from the Victoria-El Campo region of the Coastal Plain; (2) P. (O.) albaughi n. sp. from the Coastal Plain in the vicinity of Houston; and (3) P. (O.) fayettei n. sp. from the eastern versant of the Colorado River drainage south of Giddings. The three new species, P. (O.) acutus, P. (O.) texanus, and P. (O.) zonangulus form a closely allied group. They are distinguished from each other primarily by characters of the first pleopod. The subspecies P. (O.) acutus acutus and P. (O.) a. cuevachicae are elevated to full species. Species accounts are provided for all Texas subgenus members and may include diagnoses, color notes, size data, locality data, life history notes, listings of associates, and information on variation and relationships. A key to the species of Ortmannicus in Texas is also presented.
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Chemoiwa, Emily, Romulus Abila, Elizabeth Njenga, and James Barasa. "Morphological Characterization and Relationship between Morphometric Parameters and Standard Length Barbus altianalis (Boulenger, 1904) Populations in Lake Victoria Drainage Basin, Kenya." Annual Research & Review in Biology 14, no. 5 (January 10, 2017): 1–11. http://dx.doi.org/10.9734/arrb/2017/31984.
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Marchant, R., A. Hirst, R. Norris, and L. Metzeling. "Classification of macroinvertebrate communities across drainage basins in Victoria, Australia: consequences of sampling on a broad spatial scale for predictive modelling." Freshwater Biology 41, no. 2 (March 1999): 253–68. http://dx.doi.org/10.1046/j.1365-2427.1999.00429.x.
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Raburu, P. O., and F. O. Masese. "Development of a fish-based index of biotic integrity (FIBI) for monitoring riverine ecosystems in the Lake Victoria drainage Basin, Kenya." River Research and Applications 28, no. 1 (July 19, 2010): 23–38. http://dx.doi.org/10.1002/rra.1428.
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White, R. E., B. P. Christy, A. M. Ridley, A. E. Okom, S. R. Murphy, W. H. Johnston, D. L. Michalk, et al. "SGS Water Theme: influence of soil, pasture type and management on water use in grazing systems across the high rainfall zone of southern Australia." Australian Journal of Experimental Agriculture 43, no. 8 (2003): 907. http://dx.doi.org/10.1071/ea02239.
Повний текст джерелаАнотація:
Eleven experimental sites in the Sustainable Grazing Systems (SGS) national experiment were established in the high rainfall zone (HRZ, >600 mm/year) of Western Australia, Victoria and New South Wales to measure components of the water balance, and pathways of water movement, for a range of pastures from 1997 to 2001. The effect of widely spaced river red gums (Eucalyptus camaldulensis) in pasture, and of belts of plantation blue gums (E. globulus), was studied at 2 of the sites. The soil types tested ranged from Kurosols, Chromosols and Sodosols, with different subsoil permeabilities, to Hydrosols and Tenosols. The pasture types tested were kikuyu (Pennisetum clandestinum), phalaris (Phalaris aquatica), redgrass (Bothriochloa macra) and annual ryegrass (Lolium rigidum), with subterranean clover (Trifolium subterraneum) included. Management variables were set stocking v. rotational grazing, adjustable stocking rates, and level of fertiliser input. Soil, pasture and animal measurements were used to set parameters for the biophysical SGS pasture model, which simulated the long-term effects of soil, pasture type, grazing method and management on water use and movement, using as inputs daily weather data for 31 years from selected sites representing a range of climates. Measurements of mean maximum soil water deficit Sm were used to estimate the probability of surplus water occurring in winter, and the average amount of this surplus, which was highest (97–201 mm/year) for pastures in the cooler, winter-rainfall dominant regions of north-east and western Victoria and lowest (3–11 mm/year) in the warmer, lower rainfall regions of the eastern Riverina and Esperance, Western Australia. Kikuyu in Western Australia achieved the largest increase in Sm compared with annual pasture (55–71 mm), while increases due to phalaris were 18–45 mm, and those of native perennials were small and variable. Long-term model simulations suggested rooting depth was crucial in decreasing deep drainage, to about 50 mm/year for kikuyu rooting to 2.5 m, compared with 70–200 mm/year for annuals rooting to only 0.8 m. Plantation blue gums dried the soil profile to 5.25 m by an average of 400 mm more than kikuyu pasture, reducing the probability of winter surplus water to zero, and eliminating drainage below the root zone. Widely spaced river red gums had a much smaller effect on water use, and would need to number at least 14 trees per hectare to achieve extra soil drying of about 50 mm over a catchment. Soil type affected water use primarily through controlling the rooting depth of the vegetation, but it also changed the partitioning of surplus water between runoff and deep drainage. Strongly duplex soils such as Sodosols shed 50% or more surplus water as runoff, which is important for flushing streams, provided the water is of good quality. Grazing method and pasture management had only a marginal effect in increasing water use, but could have a positive effect on farm profitability through increased livestock production per hectare and improved persistence of perennial species.
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Mbabazi, Jolocam, Grace Bakyayita, John Wasswa, Andrew Muwanga, Hannington Twinomuhwezi, and Justus Kwetegyeka. "Variations in the contents of heavy metals in arable soils of a major urban wetland inlet drainage system of Lake Victoria, Uganda." Lakes & Reservoirs: Research & Management 15, no. 2 (June 29, 2010): 89–99. http://dx.doi.org/10.1111/j.1440-1770.2010.00430.x.
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Cozzi, Stefano. "Multiscale variability of ambient conditions, fast ice dynamics and biogeochemistry in the coastal zone of Victoria Land, Ross Sea." Antarctic Science 26, no. 4 (January 22, 2014): 427–44. http://dx.doi.org/10.1017/s0954102013000813.
Повний текст джерелаАнотація:
AbstractInterannual and seasonal variability of the biogeochemical characteristics of fast ice were analysed in relation to ambient conditions, water column properties and ice biota. According to Zubov's Law, the annual atmospheric cooling should generate 2.5 m thick fast ice sheets in this coastal zone, but katabatic wind peaks in July–August often cause ice breakouts, resulting in highly variable growth periods (2–9 months) and thickness (1.0–2.5 m). In spring, atmospheric forcings significantly modulate brine content (5–20%) and drainage in fast ice, as well as salinity oscillations in bottom and platelet layers (15 psu). In the water column, the formation of nutrient-impoverished Summer Surface Waters is triggered by seawater warming (-1.9 to 0.7°C), ice melting (0.03 m d-1) and pelagic production. Negative NO3 and SiO2 balances and positive NH4 balances (-41, -153 and +173 kg km-2, respectively) were estimated in fast ice in spring, whereas nutrient budgets in the platelet layer are regulated by its variable level of isolation from seawater. The large accumulation of dissolved organic carbon (3890 kg km-2) in the ice system and its release in seawater in late spring are important features of the carbon cycle in these Antarctic coastal zones, with possible implications for the modulation of climate.
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J. Kennedy, Simon, and Christopher L. Tzaros. "Foraging ecology of the Swift Parrot Lathamus discolor in the box-ironbark forests and woodlands of Victoria." Pacific Conservation Biology 11, no. 3 (2005): 158. http://dx.doi.org/10.1071/pc050158.
Повний текст джерелаАнотація:
The foraging ecology of the Swift Parrot Lathamus discolor in the box-ironbark forests and woodlands of Victoria was investigated over three years. We sought to identify features that characterized Swift Parrot foraging habitats. A total of 159 foraging sites was found, mainly in box-ironbark forests or nearby woodlands, and were located at a disproportionately high frequency on drainage lines, and a correspondingly low frequency on ridges. The species was observed foraging on 12 eucalypt and one Acacia species, but more than 90% of observations were of birds using Red Ironbark Eucalyptus tricarpa, Mugga Ironbark E. sideroxylon, Yellow Gum E. leucoxylon or Grey Box E. microcarpa. Nectar, lerp and other food from eucalypt foliage were frequent dietary items. Foraging and random sites were broadly similar in tree size-class structure. However, Swift Parrots selected trees in larger size classes for foraging more often than expected given the relative abundance of such trees. Larger trees flowered more reliably across the study area in all years. The habitat of the Swift Parrot in the study area is extensively fragmented and degraded, and management to increase the density of larger trees is recommended. We found considerable between-year variation in regional distribution and relative use of prinCipal tree species. The five identified regions within the study area all supported a significant percentage of the population in at least one of the three years. As a result, recovery measures will need to target important sites across the geographical extent of the study area.
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Dobbie, Meredith Frances. "Typing Colonial Perceptions of Carrum Carrum Swamp: The Expected and the Surprising." Land 11, no. 2 (February 18, 2022): 311. http://dx.doi.org/10.3390/land11020311.
Повний текст джерелаАнотація:
Carrum Carrum Swamp was a vast wetland to the south-east of Melbourne, Victoria, Australia, at the time that it was first sighted by white colonists in 1803. By 1878, the colonists had commenced converting the swamp to dry land for agricultural and horticultural pursuits, and 100 years later it was predominantly residential land. Shifting values in the 1970s led to environmental concerns about water quality in local creeks and Port Phillip Bay and subsequent residential development on the former swamp included the construction of stormwater treatment wetlands. Perceptions of wetlands are now diverse, including positive perceptions that support their presence in urban settings. In contrast, traditionally, wetlands have been perceived negatively, as waste lands, leading to their drainage. Nevertheless, alternative, perhaps positive, perceptions could have existed, only to be overwhelmed by the negative perceptions driving drainage. Understanding the full range of past perceptions is important to ensure that the historical record is correct and to provide historical context to contemporary perceptions of wetlands. It will better equip natural resource managers and designers and managers of constructed wetlands in urban locations to ensure that wetlands are healthy, functioning and appreciated by their local and wider communities. Thus, the perceptions of Carrum Carrum Swamp by colonists from 1803 to 1878 were examined through qualitative content analysis of historical documents, and a typology was developed. Seven different perceptions were identified: scientific, premodern, exploitative, romantic, aesthetic, medico-mythic and ecological. Most could be traced to the colonists’ predominantly British heritage, but one perception arose in the colony in response to the specific environmental conditions that the colonists encountered. This ecological perception valued wetlands as places of predictable water supply in a land of unpredictable rainfall. It recognised wetlands as part of a broader hydrological system, with influences on the local climate. Its proponents promoted the need for a different approach to the management of wetlands than in Britain and Europe. Nevertheless, a dominant exploitative perception prevailed, leading to the drainage of Carrum Carrum Swamp. The typology developed in this study will be useful for exploring perceptions of other wetlands, both colonial and contemporary.
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Amirthanathan, Gnanathikkam Emmanuel, Mohammed Abdul Bari, Fitsum Markos Woldemeskel, Narendra Kumar Tuteja, and Paul Martinus Feikema. "Regional significance of historical trends and step changes in Australian streamflow." Hydrology and Earth System Sciences 27, no. 1 (January 11, 2023): 229–54. http://dx.doi.org/10.5194/hess-27-229-2023.
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Abstract. The Hydrologic Reference Stations is a network of 467 high-quality streamflow gauging stations across Australia that is developed and maintained by the Bureau of Meteorology as part of an ongoing responsibility under the Water Act 2007. The main objectives of the service are to observe and detect climate-driven changes in observed streamflow and to provide a quality-controlled dataset for research. We investigate trends and step changes in streamflow across Australia in data from all 467 streamflow gauging stations. Data from 30 to 69 years in duration ending in February 2019 were examined. We analysed data in terms of water-year totals and for the four seasons. The commencement of the water year varies across the country – mainly from February–March in the south to September–October in the north. We summarized our findings for each of the 12 drainage divisions defined by Australian Hydrological Geospatial Fabric (Geofabric) and for continental Australia as a whole. We used statistical tests to detect and analyse linear and step changes in seasonal and annual streamflow. Monotonic trends were detected using modified Mann–Kendall (MK) tests, including a variance correction approach (MK3), a block bootstrap approach (MK3bs) and a long-term persistence approach (MK4). A nonparametric Pettitt test was used for step-change detection and identification. The regional significance of these changes at the drainage division scale was analysed and synthesized using a Walker test. The Murray–Darling Basin, home to Australia's largest river system, showed statistically significant decreasing trends for the region with respect to the annual total and all four seasons. Drainage divisions in New South Wales, Victoria and Tasmania showed significant annual and seasonal decreasing trends. Similar results were found in south-western Western Australia, South Australia and north-eastern Queensland. There was no significant spatial pattern observed in central nor mid-west Western Australia, with one possible explanation for this being the sparse density of streamflow stations and/or the length of the datasets available. Only the Tanami–Timor Sea Coast drainage division in northern Australia showed increasing trends and step changes in annual and seasonal streamflow that were regionally significant. Most of the step changes occurred during 1970–1999. In the south-eastern part of Australia, the majority of the step changes occurred in the 1990s, before the onset of the “Millennium Drought”. Long-term monotonic trends in observed streamflow and its regional significance are consistent with observed changes in climate experienced across Australia. The findings of this study will assist water managers with long-term infrastructure planning and management of water resources under climate variability and change across Australia.
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Wearne, L. J., and J. W. Morgan. "Floristic composition and variability of subalpine grasslands in the Mt Hotham region, north-eastern Victoria." Australian Journal of Botany 49, no. 6 (2001): 721. http://dx.doi.org/10.1071/bt01025.
Повний текст джерелаАнотація:
Subalpine grasslands in the Mt Hotham area, Victoria, are a common feature of cold-air drainage valleys at elevations of 1260–1660 m. Here, the pooling of cold air prevents trees from establishing and results in a distinct grassland community, composed of tussock grasses and a wide variety of intertussock species. Despite their common occurrence in the region, such grasslands have yet to be fully described. This study focused on identifying the floristic composition of subalpine grasslands across 51 sites in the vicinity of Mt Cope, Dinner Plain and Mt Hotham. The vegetation was sampled from 172, 20-m2 quadrats which were analysed by multivariate ordination techniques. Environmental variables were quantified (i.e. soil depth, pH, aspect, slope, biomass, grazing intensity, altitude). Analysis revealed that the grassland sites varied greatly in their composition and richness. There was a gradual rather than abrupt change in species composition across grassland sites, thought to be related to both the geographic proximity of the sites and environmental factors such as geology. The following five grassland types were identified from the entire data set and defined primarily by the dominant species: Poa hiemata, Poa costiniana, Poa sieberiana, Poa labillardierei and Themeda triandra. Vector-fitting revealed significant correlations between the location of the quadrats in ordination space and altitude, biomass, pH and soil depth. Both increasing altitude and biomass were associated with the P. costiniana grasslands and some of the P. hiemata grasslands. The P. hiemata grasslands were widely distibuted across altitudes and geology (i.e. basalt and metamorphic). The lower-altitude grasslands (P. labillardierei, P. sieberiana, T. triandra) were associated with increasing pH and increasing soil depth. These grasslands were of limited extent and usually occupied small areas within larger grasslands dominated by P. hiemata or P. costiniana. The floristic composition of the Hotham grasslands (1260–1630 m a.s.l.), when compared with previously published data from the higher-elevation subalpine grasslands of both the Dargo High Plains (1450–1680 m a.s.l.) and Bogong High Plains (>1700 m a.s.l.), showed that there was no distinct differentiation between grasslands of these areas. However, there was a suggestion of gradual floristic change across this geographic range. This study highlights the need for ongoing conservation of grasslands in the Hotham area, particularly those at lower altitudes (1260–1450 m a.s.l.), which represent the upper limits of many temperate grassland species.
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Sharpe, David R. "Late Glacial landforms of Wollaston Peninsula, Victoria Island, Northwest Territories: product of ice-marginal retreat, surge, and mass stagnation." Canadian Journal of Earth Sciences 25, no. 2 (February 1, 1988): 262–79. http://dx.doi.org/10.1139/e88-029.
Повний текст джерелаАнотація:
An analysis of glacial landforms on a regional scale leads to an interpretation of the dynamics of Late Wisconsinan glaciation on Wollaston Peninsula, Victoria Island, Northwest Territories. The glacial record is dominated by four adjacent belts of landforms: (I) ground moraine (till plains and ice-marginal drainage features), (II) hummocky moraine, (III) lateral and shear moraine, and (IV) streamlined landforms. The landform belts are considered as representing four distinct glacial ice conditions or regimes: (1) ice-margin retreat during extending flow of thin, active ice; (2) marginal ice stagnation following compressional flow; (3) a surging ice margin producing massive shear moraines; and (4) large-scale flooding and mass ice stagnation following a surge. These landform belts were arranged in zones by topographically controlled glacial dynamics, the latter two defining a former ice stream.Glaciological inferences can be extended by examining the sediments and processes that produced each landform set. Ground-moraine sediments were produced mainly subglacially from melt out or lodgment of glacial debris. Hummocky moraine resulted from debris flow and meltwater deposition controlled by ice, from resedimentation by sediment gravity flow, and from slump. Compressional shearing stacked thick deposits of drift prior to resedimentation. Simple lateral or end moraines may comprise interbedded sediment gravity flows deposited at static ice margins. Deformed lateral moraines resulted from intense marginal compressive flow that sheared and stacked thick, coarse sediment ridges or plates. This lateral shearing may be attributed to streaming or large ice surges. Drumlin exposures showed undeformed, interbedded, stratified sediments that appear to have accumulated in a subglacial cavity; there is no deformation related to high subglacial stress. Subglacial meltwater floods may have followed glacier surge. The greatly extended and thinner ice mass produced by the surge melted in place as clean (debris-free) ice.
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Bennett, AF. "Microhabitat use by the long-nosed potoroo, Potorous tridactylus, and other small mammals in remnant forest vegetation, south-western Victoria." Wildlife Research 20, no. 3 (1993): 267. http://dx.doi.org/10.1071/wr9930267.
Повний текст джерелаАнотація:
Microhabitat use by the long-nosed potoroo, Potorous tridactylus, and six other species of small mammal was studied in remnant forest vegetation in south-western Victoria, Australia. Throughout its geographic range, P. tridactylus is consistently associated with dense vegetation in the ground and shrub strata. However, at a local scale, captures of P. tridactylus were not clearly associated with a particular floristic group, and were not strongly correlated with any structural feature of the vegetation. Rather, individuals utilised a range of sites of differing floristic composition and vegetation density. Dense cover provided diurnal shelter and protection from predators, whereas food resources were most abundant in adjacent more open areas. The use of vegetation mosaics or ecotones that allow the inclusion of contrasting microhabitats within an individual home range appears to be characteristic of potoroids in temperate environments. Such mosaics may result from topographic or edaphic variation, or from sera1 successional stages in vegetation following disturbance. Of the other small mammals, the bush rat, Rattus fuscipes, and the brown antechinus, Antechinus stuartii, favoured floristic groups that provided dense low cover. Captures of the swamp rat, Rattus lutreolus, were clumped, and centred on several sites along the forest edge on impeded drainage where potential foods were common. The long-nosed bandicoot, Perameles nasuta, and the southern brown bandicoot, Isoodon obesulus, were uncommon and clear microhabitat preferences were not displayed. The house mouse, Mus musculus, was of transient occurrence, mostly during autumn, and no obvious habitat preference was apparent. The quality and availability of microhabitats in remnant vegetation, together with landscape structure, are important in ensuring the persistence and conservation of small mammals in fragmented landscapes.
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Wellner, J. S., A. L. Lowe, S. S. Shipp, and J. B. Anderson. "Distribution of glacial geomorphic features on the Antarctic continental shelf and correlation with substrate: implications for ice behavior." Journal of Glaciology 47, no. 158 (2001): 397–411. http://dx.doi.org/10.3189/172756501781832043.
Повний текст джерелаАнотація:
AbstractSurveys were conducted seaward of all the major drainage outlets of the Antarctic ice sheet from the Pennell Coast, north Victoria Land, to Marguerite Bay, Antarctic Peninsula. The results show that the ice sheet extended onto the outer shelf. Glacial troughs occur offshore of all major glacial outlets. Where the substrate is crystalline bedrock, ice flow tended to follow the structural grain of the bedrock, deposited little sediment and eroded the underlying bedrock. Where ice flowed over relatively soft, more easily eroded, sedimentary strata, the direction of ice flow was more directly offshore, and depositional features characterize the sea-floor. In these areas the signature of the grounded ice consists of till deposits and large-scale geomorphic features. Drumlins occur within the region of contact between crystalline and sedimentary substrates. The different geological substrates are interpreted to have exerted a fundamental control on the behavior of past ice sheets. The troughs in the areas of bedrock composed of sedimentary substrate are interpreted to have been occupied by relatively fast-flowing ice, ice streams, and the troughs in the areas of crystalline substrate are interpreted to have been occupied by slower-moving ice. The area between these two zones was characterized by ice acceleration and is marked by drumlins.
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Tory, K. J., M. E. Cope, G. D. Hess, S. Lee, K. Puri, P. C. Manins, and N. Wong. "The Australian Air Quality Forecasting System. Part III: Case Study of a Melbourne 4-Day Photochemical Smog Event." Journal of Applied Meteorology 43, no. 5 (May 1, 2004): 680–95. http://dx.doi.org/10.1175/2092.1.
Повний текст джерелаАнотація:
Abstract A 4-day photochemical smog event in the Melbourne, Victoria, Australia, region (6–9 March 2001) is examined to assess the performance of the Australian Air Quality Forecasting System (AAQFS). Although peak ozone concentrations measured during this period did not exceed the 1-h national air quality standard of 100 ppb, elevated maximum ozone concentrations in the range of 50–80 ppb were recorded at a number of monitoring stations on all four days. These maximum values were in general very well forecast by the AAQFS. On all but the third day the system predicted the advection of ozone precursors over Port Phillip (the adjacent bay) during the morning, where, later in the day, relatively high ozone concentrations developed. The ozone was advected back inland by bay and sea breezes. On the third day, a southerly component to the background wind direction prevented the precursor drainage over the bay, and the characteristic ozone cycle was disrupted. The success of the system's ability to predict peak ozone at individual monitoring stations was largely dependent on the direction and penetration of the sea and bay breezes, which in turn were dependent on the delicate balance between these winds and the opposing synoptic flow.